Method and apparatus for dehydrating wet oil, tar, and the like



Jan. 30, 1945. BURRQUGH 2,368,089

AND THE LIKE METHOD AND APPARATUS FOR DEHYDRATING WET OIL, TAR,

Filed Sept. 30, 1942 IN VE N TOR:

ME-S EURROUE EDWARD JA sh 4&

ATTORNEX Patented Jan. 30, 1945 METHOD AND APPARATUS FOR DEHYDRAT- ING WET OIL, TAR, AND THE LIKE Edward James Burrough, Ottawa, Ontario, Canada, assignor to Maurice Donovan Curran, Webster Groves, Mo.

Application September 30, 1942, Serial No. 460,314

In Canada September 23, 1942 6 Claims.

This invention relates to the treatment of crude oils and tars, and more particularly to the separation of oil or tar and water emulsions of the more persistent type.

One of the common problems in the treatment of such emulsions is the presence of excessive foaming when substantial volumes of the emulsion are heated rapidly. In order to avoid such foaming, the treatment may be carried out under low heat or under substantial pressure, both of which are cumbersome and expensive. Since the use of low heat is impractical inasmuch as it results in a long period of treatment, it is now usual to carry out the distillation of oil emulsions under pressure substantially greater than atmospheric.

It is an object of the present invention to provide for the rapid, continuous and readily controlled treatment of an emulsion of the type referred to under atmospheric pressure. A further object is to provide simple, compact apparatus for carrying out such treatment. Another object is to provide an apparatus of the type mentioned which is entirely self-contained and readily portable for convenient transport to any area in, for instance, an oil field, where it may be employed.

Other objects and advantages of the invention will be apparent from the ensuing description, with particular reference to the accompanying drawing, in which,

Figure 1 is a longitudinal section of an apparatus for carrying out the treatment,

Figure 2 is a transverse section,

Figure 3 is a view of one end of the apparatus, and

Figure 4 is a view of the other end of the apparatus.

In the drawing, l is a heating shell having a plurality of heating tubes 2 extending longitudinally therethrough. As shown, the tubes are disposed in a horizontal plane at substantially the midsection of the shell. The tubes are packed with a refractory material 3, such as crushed fire brick of about inch to inch mesh size. The ends of the tubes extend slightly beyond the end walls of the shell, those at one end of the shell being open and provided with elbows 4, which serve to retain the packing in the tubes, and those at the other end of the shell being provided with caps 5 having orifice tubes, 6, extending therethrough. Gas and air are fed to the fire tubes from a common header 7 to which the orifice tubes of the burners are attached. The header is preferably provided with a Y connection 8 and a seal pot 9 for uniform distribution of pressure at the burner orifice. The pressure of the gas-air mixture may be approximately 7 inches indicated on the water gauge [0 and may be supplied from a positive type blower H having an air intake l2 and a gas inlet l3, with a gauge It, pressure governor l5 and valve Hi.

The shell is divided into two zones-a heating zone and a heat exchanger zone-b y means of the spaced baiiie plates ll and I8 extending inwardly from the end walls to direct the upward flow of the oil or the like under treatment from the feed pipe [9 through which the oil is led under atmospheric pressure.

Between the heating tubes 2 are located overflow weirs 2B which discharge into a chamber 2! from which a series of heat exchange pipes 22 extend longitudinally of the shell into a launder 23 for discharge through the pipe 24. The inlet to the overflow weirs is but slightly above the heating tubes as shown, thus the liquid level is but slightly above the heating tubes. For inspection and cleaning there is provided a manhole 25 in the end of the shell above the burners, plugs 26 into the heat exchange header, a removable cover 21 below the exhaust end of the fire tubes and a drain pipe 28 in the base of the shell. The unit is provided with insulation 29, particularly for the upper section to prevent condensation on the inner side of the shell.

Connected to the top of the shell is a condenser 30 which discharges into a separator it from which the portion of light distilled fraction may be withdrawn through the pipe 32 and water from the bottom of the separator through the pipe 33. Thermometers 3d and 35 may be provided for regulating the heat input to maintain the dehydrating temperature.

In operation, the oil or tar emulsion or the like to be dehydrated is fed by gravity into the unit at atmospheric pressure through the pipe l9. The liquid rises about the heat exchange pipes 22 and is directed by the baflle plates l8 and I! to first contact the burner tubes 2 adjacent the exhaust end thereof. The level of the weir outlet maintains a substantially thin layer of liquid above the hot tubes and the water is driven off substantially without foaming. The distillate consisting of water and a small portion light spirit is condensed and separated as indicated.

The hot dehydrated liquid flows through the weirs to and through the heat exchanger, substantially in countercurrent to the incoming fluid, thus preheating the latter and recovering much or the heat from the dehydrated liquid, which passes in cooled form to storage. The heat input being constant, the continuous operation oi the unit may be rerulated by adjustment of the flow of wet tar to the system.

This method and apparatus for dehydrating such liquids have been found to be particularly efllcient in avoiding foaming and economical in operation. For example, a shell of 5 feet in diameter and 5 feet long of the construction shown will readily dehydrate 200 gallons per hour of wet or emulsified tar.

I claim:

1. Apparatus for dehydrating wet tar, oil and other liquid which comprises a chamber having therein a heating zone and beneath the latter a heat exchange zone, internally heated pipes in the former zone and heat exchange tubes in the latter zone, means for delivering hydrated liquid through the heat exchange zone to contact said tubes, and a series of weirs adjacent the heating pipes for maintaining the liquid about the pipes at a level only slightly above their upper surface and means for delivering hot dehydrated liquid from the weirs to said heat exchange tubes.

2. Apparatus as defined in claim 1 having means for delivering liquid at substantially atmospheric pressure adjacent the bottom of said chamber.

3. Apparatus for dehydrating wet tar, oil and the like which comprises a cylindrical chamber, a series of internally heated pipes horizontally disposed substantially midway of the chamber, means at one end of said tubes for heating the same, weir means for maintaining a constant liquid level about said tubes, heat exchange tubes beneath the heating pipes, means for admitting the hydrated liquid to the chamber beneath said tubes and means for delivering hot dehydrated liquid to said tubes.

i. Apparatus as defined in claim 3 having means for delivering liquid at normal pressure adjacent the bottom of said chamber, and baflle means for directing the flow of liquid passing around the heat exchange tubes to the exhaust end Of the heating tubes.

5. Apparatus for dehydrating wet tar, oil and the like fluid comprising a chamber, a series of fire tubes horizontally disposed substantially midway of the chamber means for maintaining a substantially constant fiuid level slightly above said fire tubes, heat exchange tubes beneath the fire tubes, means for passing dehydrated fluid through said heat exchange tubes, means where by the hydrated fluid at substantially atmospheric pressure is passed into the chamber adjacent its bottom and upwardly about the heat exchanger and fire tubes and in its dehydrated condition continuously downwardly through theheat exchange tubes and means for removing from the chamber water vapour distilled from the fluid to maintain substantially atmospheric pressure within the chamber.

6. A method of dehydrating oil emulsions and the like which comprises maintaining a body of emulsion at a substantially constant level in a reaction zone, feeding emulsion to said body ad.

jacent the bottom of said zone, heating the emulsion adjacent the surface of said body by indirect firing to dehydrate the same, withdrawing dehydrated fluid from said body adjacent the top thereof and causing the hot dehydrated fluid to flow downwardly in heat exchange re1ationship with the rising lower portion of the body of emulsion to preheat the latter and withdrawing water vapour from above said body to maintain substantially atmospheric pressure in said zone.

EDWARD JAMES BURROUGH. 

